The major purpose of this project is to collaborate with national investigators and NIDA in the confirmatory multivariate analysis of approximately 30 important data sets to test drug abuse theories using innovative modern statistical methods. This is done by locating significant existing drug abuse data sets collected among dysfunctional, at-risk populations that have not been fully analyzed, particularly with newer theory-testing methods; performing meaningful analyses of these data using plausible models and theoretical frameworks; and, based on these analyses, preparing well-researched and well-written reports for scientific publication in collaboration with the original researchers who generated the data. In addition, technical, statistical, and methodological assistance is provided to drug abuse researchers, NIDA, and other governmental agencies.